• Asian-Australasian Journal of Animal Sciences
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• 제7권4호
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• pp.475-479
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• 1994

Postweaning performance data were obtained on 401 group fed purebred Angus calves from 24 selected sires (12 high and 12 low feed conversion sires) from 1983 through 1986 at the Northwestern Branch of the Ohio Agricultural Research and Development Center. A single generation divergent selection experiment was replicated four times (1983, 1984, 1985 and 1986) to obtain an realized heritability estimate for postweaning feed conversion. The 140-d postweaning period was divided into five 28-d periods. Realized heritability estimates for feed conversion by 28-d periods fluctuated greatly and demonstrated no particular pattern. Heritability was highest for the fourth period (between d 85 and 112 of postweaning period, 0.61). Thus, beef producers could successfully select for feed conversion.

• Asian-Australasian Journal of Animal Sciences
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• 제18권8호
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• pp.1075-1079
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• 2005

The main objective of this study is to examine genetic changes in growth rate and carcass composition traits in group housed, ad libitum fed pigs, from lines of Large White divergently selected over four years for high and low post-weaning daily gain on a fixed but restricted ration. Genetic parameters for production and carcass traits were also estimated by using average information-restricted maximum likelihood applied to a multivariate individual animal model. All analyses were carried out on 1,728 records of group housed ad libitum fed pigs, and include a full pedigree of 5,324 animals. Estimates of heritability (standard errors in parentheses) were 0.11 (0.04) for lifetime daily liveweight gain (LDG), 0.13 (0.04) for daily carcass weight gain (CDG) and 0.28 (0.06) for carcass backfat (CFT). Genetic correlations between LDG and CDG were highly positive and between LDG and CFT negative, suggesting that selection for lifetime daily gain under commercial conditions of group housing with ad libitum feeding would result in favourable improvement in carcass traits. CFT showed negative genetic correlations with CDG. Correlated genetic responses evaluated as estimated breeding values (EBVs) were obtained from a multivariate animal model-best linear unbiased prediction analysis. After four years of divergent selection for 6 week post-weaning growth rate on restricted feeding, pigs performance tested on ad libitum feeding in groups exhibited changes in EBVs of 6.77 and -9.93 (g/d) for LDG, 4.25 and -7.08 (g/d) for CDG, and -1.42 and 1.55 (mm) for CFT, in the high and low lines, respectively. It is concluded that selection for growth rate on restricted feeding would significantly improve genetic performance and carcass composition of their descendants when group housed and ad libitum fed as is a common commercial practice.

• Asian-Australasian Journal of Animal Sciences
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• 제28권6호
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• pp.876-887
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• 2015

Dicer, an ribonuclease type III type endonuclease, is the key enzyme involved in biogenesis of microRNAs (miRNAs) and small interfering RNAs (siRNAs), and thus plays a critical role in RNA interference through post transcriptional regulation of gene expression. This enzyme has not been well studied in the Indian water buffalo, an important species known for disease resistance and high milk production. In this study, the primary coding sequence (5,778 bp) of bubaline dicer (GenBank: AB969677.1) was determined and the bubaline Dicer1 biocomputationally characterized to determine the phylogenetic signature among higher eukaryotes. The evolutionary tree revealed that all the transcript variants of Dicer1 belonging to a specific species were within the same node and the sequences belonging to primates, rodents and lagomorphs, avians and reptiles formed independent clusters. The bubaline dicer1 is closely related to that of cattle and other ruminants and significantly divergent from dicer of lower species such as tapeworm, sea urchin and fruit fly. Evolutionary divergence analysis conducted using MEGA6 software indicated that dicer has undergone purifying selection over the time. Seventeen divergent sequences, representing each of the families/taxa were selected to study the specific regions of positive vis-$\grave{a}$-vis negative selection using different models like single likelihood ancestor counting, fixed effects likelihood, and random effects likelihood of Datamonkey server. Comparative analysis of the domain structure revealed that Dicer1 is conserved across mammalian species while variation both in terms of length of Dicer enzyme and presence or absence of domain is evident in the lower organisms.

• 한국과학교육학회지
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• 제28권5호
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• pp.482-494
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• 2008

본 연구에서는 창의적 사고력은 협의의 측면으로 정의하여 제시하였고 그리고 비판적 사고력은 강한 의미의 측면으로 정의하여 제시하였으며, 이를 토대로 하여 현행 탐구 교수 전략을 수정 보완하는데 활용할 수 있는 창의적 사고력과 비판적 사고력 신장 모델을 개발하였다. 이 모델은 교사가 물어보는 인과적 질문에 대하여 학생들로 하여금 발산적 사고력을 활용하면서 조별 토론에 의하여 잠정적 설명들을 적어도 세 가지로 응답들을 하게 한 후에, 이어서 조 별 토론하면서 보다 더 나은 하나의 설명(가설)을 선택하도록 하는 가설을 제안하는 과정이다. 발산적인 사고로 다양한 가설들을 만들어 내기 위해서도 조 별 협동학습 활동이 필수적이며, 또한 학생들로 하여금 강한 의미의 비판적 사고를 형성하게 하기 위해서도 반드시 협동 학습에서 조 별 토론에 의하여 얻어진 사고의 결과들을 만들어 내도록 하여야 한다. 이러한 과정을 경험하면서 학생들은 창의적인 사고와 비판적인 수렴적 사고를 작동하게 되는 것이다. 이 창의적 사고력과 비판적 사고력 신장 모델을 적용한 수업 전략에는 기존 수업 전략에 비하여 아주 조그마한 차이만을 보여주나, 이와 같은 창의적 사고력과 비판적 사고력을 활용한 탐구 교수 전략을 중학교 2학년 학생들과 대학교 1학년 학생들에게 적용한 결과에 의하면 비교반과 비교하였을 때 유의미하게 창의력이 신장되었다. 창의적 사고력과 비판적 사고력 신장 모델을 활용한 다양한 여덟 개의 실례들을 개발하였다. 이 여덟 개의 결과들은 기존의 탐구 교수 전략에 들어 있는 인과적 질문에 대하여 설명들(가설들)을 하고 있는 형태들을 갖추고 있다.

• Journal of Animal Science and Technology
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• 제62권3호
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• pp.293-305
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• 2020

The difference in the breeding programs and population history may have diversely shaped the genomes of Korean native cattle breeds. In the absence of phenotypic data, comparisons of breeds that have been subjected to different selective pressures can aid to identify genomic regions and genes controlling qualitative and complex traits. In this study to decipher genetic variation and identify evidence of divergent selection, 3 Korean cattle breeds were genotyped using the recently developed high-density GeneSeek Genomic Profiler F250 (GGP-F250) array. The three Korean cattle breeds clustered according to their coat color phenotypes and breeding programs. The Heugu breed reliably showed smaller effective population size at all generations considered. Across the autosomal chromosomes, 113 and 83 annotated genes were identified from Hanwoo-Chikso and Hanwoo-Heugu comparisons, respectively of which 16 genes were shared between the two pairwise comparisons. The most important signals of selection were detected on bovine chromosomes 14 (24.39-25.13 Mb) and 18 (13.34-15.07 Mb), containing genes related to body size, and coat color (XKR4, LYN, PLAG1, SDR16C5, TMEM68, CDH15, MC1R, and GALNS). Some of the candidate genes are also associated with meat quality traits (ACSF3, EIF2B1, BANP, APCDD1, and GALM) and harbor quantitative trait locus (QTL) for beef production traits. Further functional analysis revealed that the candidate genes (DBI, ACSF3, HINT2, GBA2, AGPAT5, SCAP, ELP6, APOB, and RBL1) were involved in gene ontology (GO) terms relevant to meat quality including fatty acid oxidation, biosynthesis, and lipid storage. Candidate genes previously known to affect beef production and quality traits could be used in the beef cattle selection strategies.

• 영재교육연구
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• 제24권4호
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• pp.679-701
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• 2014

영재선발을 위한 교사 관찰 추천의 타당성 문제가 꾸준히 제기되고 있는 가운데, 이 연구는 과학영재 선발을 위한 교사 추천(지명)의 타당성을 분석하고자 하였다. 타당성의 준거변인으로 과학적 문제해결력, 과학적 태도와 같은 영역 특수적 변인과 확산적 사고, 창의적 인성, 내재적 동기, 리더십과 같은 영역 일반적 변인이 사용되었다. 현재 영재교육을 받고 있는 과학영재 학생, 영재교육을 받은 적은 없지만 교사에 의해 영재로 판단되어 추천된 잠재영재 학생, 그리고 일반학급의 학생들이 연구대상으로 참여하였다. 분산분석 결과, 창의적 문제해결력의 하위 변인인 독창성과 확산적 사고의 하위 변인인 유창성과 독창성을 제외한 모든 변인에서 영재학생/추천학생과 일반학생 간에 유의한 차이가 발견되었다. 즉, 영재학생/추천학생은 이들 변인에서 일반학생보다 우수한 것으로 나타났다. 판별분석 결과, 영재학생/추천학생을 일반학생과 유의하게 판별해주는 함수가 도출되었으며, 판별함수에 부하된 변인은 독창성을 제외한 과학 창의적 문제해결력과 과학효능감으로 나타났다. 이러한 결과는 교사가 과학영재 학생을 추천할 때 논리적 사고나 문제해결력, 과학수행, 그리고 이로 인해 강화되는 과학효능감과 같이 보다 '적응' 지향적인 학문적 탁월성을 고려하는 반면, 다양한 새로운 반응들을 신속하게 생성해내는 '혁신' 지향적인 속성(유창성이나 독창성으로 나타나는)은 덜 고려한다는 것을 말해준다. 또한 교사추천의 기준은 학문적 탁월성을 지향하는 과학영재교육기관의 선발기준과도 부합하며, 이러한 기준으로 영재를 판별할 때는 교사추천만으로도 영재판별이 가능함을 시사한다.

• Journal of Animal Science and Technology
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• 제65권3호
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• pp.596-610
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• 2023

Focusing high marble deposition, Hanwoo feedlot system uses high-energy diet over the prolonged fattening period. However, due to the individual genetic variation, around 40% of them are graded into inferior quality grades (QG), despite they utilized the same resources. Therefore, focusing on development of a nutrigenomic based precision management model, this study was to evaluated the response to the divergent selection on genetic merit for marbling score (MS), under different dietary total digestible nutrient (TDN) levels. Total of 111 calves were genotyped and initially grouped according to estimated breeding value (high and low) for marbling score (MS-EBV). Subsequently, managed under two levels of feed TDN%, over the calf period, early, middle, and final fattening periods following 2 × 2 factorial arrangement. Carcasses were evaluated for MS, Back fat thickness (BFT) and Korean beef quality grading standard. As the direct response to the selection was significant, the results confirmed the importance of initial genetic grouping of Hanwoo steers for MS-EBV. However, dietary TDN level did not show an effect (p > 0.05) on the MS. Furthermore, no genetic-by-nutrition interaction for MS (p > 0.05) was also observed. The present results showed no correlation response on BFT (p > 0.05), which indicates that the selection based on MS-EBV can be used to enhance the MS without undesirable effect on BFT. Ultimate turnover of the Hanwoo feedlot operation is primarily determined by the QGs. The present model shows that the initial grouping for MS-EBV increased the proportion of carcasses graded for higher QGs (QG1⁺⁺ and QG1⁺) by approximately 20%. Moreover, there appear to be a potential to increase the proportion of QG 1⁺⁺ animals among the high-genetic group by further increasing the dietary energy content. Overall, this precision management strategy suggests the importance of adopting an MS based initial genetic grouping system for Hanwoo steers with a subsequent divergent management based on dietary energy level.

• Educational Technology International
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• 제14권2호
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• pp.167-187
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• 2013

Team project learning is a type of Project-Based Learning, which is an effective learning method for developing collaborative competency and interpersonal communication skills, as well as for developing cognitive competency such as critical thinking, creative thinking, and analytical skills. This research, conducted to analyze learning activities, focuses on students' creative thinking and activities in TPBL(Team Project-Based Learning). A qualitative approach including a reflective journal based on the 6 stages of TPBL, was adopted for this purpose. In this study, 69 reflective journals on the three stages (developing a theme, researching, theme-making) of 23 undergraduate students were categorized on the basis of three criteria: divergent thinking factors, convergent thinking factors and affective factors. The results show that the participants' journals demonstrated twenty-eight activities from nine cognitive factors and nine activities from three affective factors were derived from reflect journal. This finding indicates that more appropriate instructional strategies are needed for students to enhance their creative thinking skills and activities

• The Plant Pathology Journal
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• 제33권3호
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• pp.296-306
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• 2017

Sugarcane mosaic virus (SCMV) is one of the most damaging viruses infecting sugarcane, maize and some other graminaceous species around the world. To investigate the genetic diversity of SCMV in Iran, the coat protein (CP) gene sequences of 23 SCMV isolates from different hosts were determined. The nucleotide sequence identity among Iranian isolates was more than 96%. They shared nucleotide identities of 75.5-99.9% with those of other SCMV isolates available in GenBank, the highest with the Egyptian isolate EGY7-1 (97.5-99.9%). The results of phylogenetic analysis suggested five divergent evolutionary lineages that did not completely reflect the geographical origin or host plant of the isolates. Population genetic analysis revealed greater between-group than within-group evolutionary divergence values, further supporting the results of the phylogenetic analysis. Our results indicated that natural selection might have contributed to the evolution of isolates belonging to the five identified SCMV groups, with infrequent genetic exchanges occurring between them. Phylogenetic analyses and the estimation of genetic distance indicated that Iranian isolates have low genetic diversity. No recombination was found in the CP cistron of Iranian isolates and the CP gene was under negative selection. These findings provide a comprehensive analysis of the population structure and driving forces for the evolution of SCMV with implications for global exchange of sugarcane germplasm. Gene flow, selection and somehow homologous recombination were found to be the important evolutionary factors shaping the genetic structure of SCMV populations.

• Asian-Australasian Journal of Animal Sciences
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• 제21권10호
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• pp.1389-1394
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• 2008

Abdominal fat characters are complex and economically important in the poultry industry. Their selection may benefit from the implementation of marker-assisted selection (MAS). The objective of this study was to identify the markers linked to QTL responsible for fatness traits. The Northeast Agricultural University broiler lines divergently selected for abdominal fat content (NEAUHLF) were used in the study. A total of 596 individuals from the divergent tails from the 6th to the 10th generations were genotyped at 23 microsatellite markers on chromosome 1. The differences of allele frequencies of all marker alleles between the divergent tails across the five generations were recorded. The allele frequencies of five markers, including LEI0209, LEI0146, MCW0036, ADL328 and MCW0115, had significant differences between the two tails in all five generations. The resulting p-values using Fisher's exact test on eleven markers, containing MCW248, MCW0010, MCW0106, LEI0252, LEI0068, MCW0018, MCW0061, LEI0088, MCW200, MCW283 and ROS0025, had a decreasing tendency from the 6th to the 10th generation. Statistical analysis showed that polymorphisms of the eight markers, including LEI0209, LEI0146, ROS0025, MCW0115, MCW0010, MCW0036, MCW283, ADL328, were significantly (p<0.0011) or suggestively (p<0.05) associated with abdominal fat content (AFW and AFP) across generations. It is concluded that the eight markers could be associated with the QTL affecting the deposition of abdominal fat in broiler chickens.